How to reset/add user/password in Windows 10 without login

What happen when you forgot your password to log into Windows 10 and there is no other account that you could log into?

Turn out Windows 10 has a hidden feature which can be very handy in this situation!

Boot the computer with a Windows 10 Installation CD or Win10PE
Once in the command prompt:

move C:\Windows\System32\utilman.exe C:\Windows\System32\utilman.exe.bat
copy C:\Windows\System32\cmd.exe C:\Windows\System32\utilman.exe

Reboot the computer normally.
When you get to the login screen, normally under bottom right corner, there is this Ease Of Access button ease-of-access-icon1. Which is now replaced with CMD.

Open the command prompt:

net user <username> <password> /add
net localgroup administrators <username> /add

That's it. You could now login with that newly created administrator account and reset your forgotten password for that accout!

Reference from here